A mistake that made me very happy. :-) :-) :-)

[HP-Collection]

Maybe sometimes backplates were removed and exchanged by HP during service?

[Thomas Okken]

(11-15-2018 09:46 PM)HP-Collection Wrote:  Maybe sometimes backplates were removed and exchanged by HP during service?

I had my HP-25 repaired by HP, back in 1977. When I got it back, it was a whole new calculator (it had turned into a 25C, how's that for out-of-warranty service!). The only part that was from my original calculator was the back of the case, presumably so I'd still have the same serial number.

[rprosperi]

(11-16-2018 05:41 AM)Thomas Okken Wrote:  The only part that was from my original calculator was the back of the case, presumably so I'd still have the same serial number.

Exactly correct, as this determines the original mfg date, and therefore also your warranty period, support entitlements, etc. If further service or support is required in the future, you would still have the same 'original' machine info to give them.

I quite recently worked on an HP-41C that had been in for HP service at some point; HP replaced the front half of the machine (no idea what the problem was) but retained the original rear case (with s/n), I/O block and even the original black plastic sheet that separates the CPU board from the keyboard, and had even written the original s/n on the sheet. My guess is the front half and the sheet were separate 'service parts' and the repair process was constrained to replace the minimum number of parts.

[aurelio]

(11-16-2018 02:48 PM)rprosperi Wrote:  

(11-16-2018 05:41 AM)Thomas Okken Wrote:  The only part that was from my original calculator was the back of the case, presumably so I'd still have the same serial number.

Exactly correct, as this determines the original mfg date, and therefore also your warranty period, support entitlements, etc. If further service or support is required in the future, you would still have the same 'original' machine info to give them.

I quite recently worked on an HP-41C that had been in for HP service at some point; HP replaced the front half of the machine (no idea what the problem was) but retained the original rear case (with s/n), I/O block and even the original black plastic sheet that separates the CPU board from the keyboard, and had even written the original s/n on the sheet. My guess is the front half and the sheet were separate 'service parts' and the repair process was constrained to replace the minimum number of parts.

I've a serviced 41 with erased SN on the rear case, the SN was applied after servicing on a label inside the batt. compartment

[rprosperi]

(11-16-2018 06:12 PM)aurelio Wrote:  I've a serviced 41 with erased SN on the rear case, the SN was applied after servicing on a label inside the batt. compartment

When service required replacement of the rear case (e.g. if the recessed boss to hold the screw head under the top rubber feet broke off the case - an all too common problem) they often supplied a new rear case with no serial number engraved on the case (leaving the SN area blank) and then put a similar label inside the battery bay, but I never heard of an 'erased' SN. How was this done? e.g. was it scratched or ground off?

[aurelio]

(11-17-2018 12:56 AM)rprosperi Wrote:  

(11-16-2018 06:12 PM)aurelio Wrote:  I've a serviced 41 with erased SN on the rear case, the SN was applied after servicing on a label inside the batt. compartment

When service required replacement of the rear case (e.g. if the recessed boss to hold the screw head under the top rubber feet broke off the case - an all too common problem) they often supplied a new rear case with no serial number engraved on the case (leaving the SN area blank) and then put a similar label inside the battery bay, but I never heard of an 'erased' SN. How was this done? e.g. was it scratched or ground off?

excuse me Bob, I meant "blank" and I wrote erased...

[rprosperi]

(11-17-2018 07:13 AM)aurelio Wrote:  excuse me Bob, I meant "blank" and I wrote erased...

No problem Aurelio.

That makes sense, just the same as several others I've seen. Seeing a blank SN pad on a 41 is an easy clue that it's a 'frankencalc'.

[aurelio]

(11-17-2018 02:13 PM)rprosperi Wrote:  

(11-17-2018 07:13 AM)aurelio Wrote:  excuse me Bob, I meant "blank" and I wrote erased...

No problem Aurelio.

That makes sense, just the same as several others I've seen. Seeing a blank SN pad on a 41 is an easy clue that it's a 'frankencalc'.

Here's what we are talking about.